Marijuana Use Per Se Not a ‘Gateway’ To Illicit Drug Use, Study Says

Pittsburgh, PA:  Adolescent marijuana use is not a reliable predictor of later substance abuse, according to clinical trial data published this month in The American Journal of Psychiatry.
Investigators at the University of Pittsburgh, School of Pharmacy, tracked the drug use patterns of 214 boys, beginning at ages 10 to 12, for a period of up to twelve years.  All of the subjects eventually used either legal or illegal drugs. Researchers found that adolescents who used marijuana prior to using other drugs, including alcohol and tobacco, were no more likely to develop a substance abuse disorder than other subjects in the study.
The study’s findings “call into question the long-held belief that has shaped prevention efforts and governmental policy for six decades,” researchers declared in a press release.
Investigators said that environmental factors (e.g., a greater exposure to illegal drugs in their neighborhoods) as well as subjects’ “proneness to deviancy” were the two characteristics that most commonly predicted substance abuse.
“This evidence supports what’s known as the common liability model … [which] states [that] the likelihood that someone will transition to the use of illegal drugs is determined not by the preceding use of a particular drug, but instead by the user’s individual tendencies and environmental circumstances,” investigators stated in a press release.  They added, “The emphasis on the drugs themselves, rather than other, more important factors that shape a person’s behavior, has been detrimental to drug policy and prevention programs.”
A 1999 review by US National Academy of Science’s Institute of Medicine also disputed the hypothesis that cannabis use is a stepping-stone to other illicit drug use, concluding that pot was not a “gateway drug to the extent that it is a cause or even that it is the most significant predictor of serious drug abuse.”
For more information, please contact Allen St. Pierre, NORML Executive Director, or Paul Armentano. NORML Senior Policy Analyst, at (202) 483-5500.  Full text of the study, “Predictors of marijuana use in adolescents before and after licit drug use: examination of the gateway hypothesis,” appears in the December issue of The American Journal of Psychiatry.  Further discussion of this study is available on the December 6, 2006 edition of NORML’s daily AudioStash at: